Source : Webster's Revised Unabridged Dictionary (1913)

Customarily \Cus"tom*a*ri*ly\ (-[asl]*r[i^]*l[y^]), adv.
   In a customary manner; habitually.

Source : WordNet®

customarily
     adv : by custom; according to common practice; "children are
           customarily expected to be seen but not heard"